1. Field of the Invention
The present invention relates generally to a multiple rotor disc assembly having a threaded connection, and more specifically to a threaded connection having a centrifugally engaging lock pin to prevent the threaded connection from loosening during operation. The present invention is directed to a rotor disc assembly of a gas turbine engine, but can be used in rotor discs of non-gas turbines.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
Rotor disc assemblies are found in gas turbine engines or other turbomachinery such as compressors and pumps. When more than one row of blades is used, additional rotor discs are secured together and rotate as one unit. There are several well known methods of securing adjacent rotor discs together such as welding, bolting, and threading. The welded and bolted discs tend to remain secured together. However, the welded and bolted discs are generally difficult to separate for maintenance or repair of discs. Threaded discs are easy to assemble or disassemble, but can become loose from the rotational operation. What is needed is an easy method of securing adjacent rotor discs together that will maintain a secure connection, especially while rotation occurs, yet will provide for an easy assembly or disassembly of the discs when rotation has stopped.
U.S. Pat. No. 4,477,227 issued to Klufas on Oct. 16, 1984 and entitled KEYING FOR SHRUNK-ON TURBINE WHEELS shows a turbine rotor disk assembly in which the rotor disks are shrink fitted together to prevent relative rotation. This method of securing the rotor disks would not allow for easy disassembly and prevent loosening of the assembled rotor disks during operation.
U.S. Pat. No. 5,388,963 issued to Dimmick, III et al on Feb. 14, 1995 entitled FLANGE FOR HIGH SPEED ROTORS shows rotor disks fastened together by a plurality of nut and bolt assemblies. This type of connection is somewhat easy to disassemble the rotor disks. However, the present invention provides for an even easier disassembly. Also, the nut and bolt assembly can come loosened due to the vibrations during operation. The present invention provides for an improved method of preventing loosening of the rotor disks during rotation.
U.S. Pat. No. 5,860,789 issued to Sekihara et al on Jan. 19, 1999 entitled GAS TURBINE ROTOR shows a plurality of rotor disks fastened together in an axial direction by stacking bolts. The stacking bolt passes through the entire series of rotor disks. Therefore, to disassembly one rotor disk requires that all rotor disks be disassembled. Also, the stacking bolts could come loosened from vibrations during rotation.